In some instances, it may be difficult to suppress and/or extinguish a fire due to the nature of the location of the fire. For example, a fire associated within an interior of a container may be difficult to suppress and/or extinguish because it may be difficult to deliver an effective extinguishing agent to the location of the container and/or it may be difficult to deliver an effective extinguishing agent to the interior of the container, so that the extinguishing agent may be applied to the fire.
An example of a fire that may be difficult to suppress and/or extinguish due to the nature of the location of a fire may include fires associated with cargo. For example, cargo fires on board freighter aircraft may be intrinsically dangerous and/or difficult to extinguish because, for example, access to the cargo area may be restricted or impractical once the cargo has been positioned within the freighter aircraft.
For example, the airfreight industry uses containers and pallets, which are sometimes generically referred to as “Unit Load Devices” or “ULDs,” to consolidate and ship freight. Such containers, for example, may be constructed of various materials, such as aluminum, fiberglass, and/or other suitable materials. Such containers, when loaded into freighter aircraft, enclose and restrain the freight. Furthermore, such containers may include features configured to engage retractable locks located in, for example, an aircraft floor cargo handling system, which may provide desirable fore-aft, lateral, and/or vertical restraint during ground and flight operations.
Cargo containers may be typically loaded in “sticks” of two (i.e., two containers are placed across the width of the cargo area, such as a freighter aircraft fuselage). An example of a typical container widely used is designated “AMJ” under National Aerospace Standard 3610. An AMJ defines a roughly rectangular box having an upper edge on one side that may be chamfered or curved, for example, to follow the cross-sectional geometry of an aircraft fuselage. The AMJ has a base dimension of about 125 inches long by about 96 inches wide, and a height dimension of about 96 inches (i.e., on the non-chamfered/non-curved side). Other containers are known to those skilled in the art, and perhaps two-dozen containers of differing sizes are commonly used.
Once loaded into the cargo area of a freighter aircraft fuselage, only the most forward containers may be accessible to flight crews. Even the most forward containers, however, may permit only limited access thereto. If a fire were to occur in a container aft of the forward containers, there may be no practical way to manually deliver a fire-extinguishing agent to the fire.
One possible option would be to install a fixed, automatically-actuated, bottle-type fire suppressant device in each container. Due to high cost, high weight, and/or maintenance considerations, it may be impractical to install such devices in each container. In particular, an airfreight operator may have many thousands of containers in inventory at any one time. Furthermore, according to a common industry practice sometimes referred to as “interlining,” airfreight operators temporarily share and/or exchange containers. Such a practice might lead to a lack of cargo protection, for example, for instances in which an airfreight operator borrows containers from another airfreight operator who does not install such devices.
Another possible option would be to install pyrotechnic gas generator devices or cartridges in each container. Pyrotechnic gas generator devices may provide a lightweight and efficient method of suppressing and/or extinguishing container fires. The installation of such devices in each container, however, may be undesirable for a number of reasons. For example, these devices may be prohibitively expensive in light of the large number of containers involved. Furthermore, cargo containers may often be exposed to shocks, vibrations, and/or temperature extremes for extended periods of time. Such exposure could result in damage to the devices, such as, for example, cracks in the propellant. Such damage might render such devices dangerous and/or ineffective.
For these and other reasons, there is a need for alternative approaches that may overcome one or more of the above-outlined drawbacks with the options described above.
One subject of the invention relates to suppressing and/or extinguishing a fire associated with a container located where manual application of a fire extinguishing agent may be impractical. A further subject of the invention relates to suppressing and/or extinguishing a fire associated with a container that does not require locating a fire extinguishing device within the container. Yet another subject of the invention relates to suppressing and/or extinguishing a fire associated with a container located in a cargo area. Still a further subject of the invention relates to suppressing and/or extinguishing a fire associated with a container by delivering a fire extinguishing agent to the interior of the container. A further subject of the invention relates to suppressing and/or extinguishing a fire associated with a container that does not unduly hinder processes associated with moving the container into a cargo area.
The invention may seek to satisfy one or more of the above-mentioned subjects. Although the present invention may obviate one or more of the above-mentioned desires, it should be understood that some aspects of the invention might not necessarily obviate them.